Replace str.format() with str.join() for faster string concatenation

[SaFE-APIOpt]

misp-warninglists/tools/generate-google.py

Line 25 in 4df816b

domain = "{}".format(domain[0])

Current code:

if len(domain) is 1 :
    domain = "{}".format(domain[0])
elif len(domain) is 2 :
    domain = "{}{}".format(domain[0], domain[1])
elif len(domain) is 3 and not "[" in domain[2]:
    domain = "{}{}".format(domain[0], domain[2])
else:
    domain = "{}{}".format(domain[0], domain[1])

Proposed replacement:

if len(domain) is 1:
    domain = ''.join([domain[0]])
elif len(domain) is 2:
    domain = ''.join([domain[0], domain[1]])
elif len(domain) is 3 and '[' not in domain[2]:
    domain = ''.join([domain[0], domain[2]])
else:
    domain = ''.join([domain[0], domain[1]])

str.join() is more efficient for string concatenation because it first calculates the total length of all strings, allocates memory once, and then performs the concatenation in a single pass. In contrast, str.format() needs to parse the format template and convert each argument before concatenation, which introduces extra overhead. Therefore, replacing str.format() with ''.join() improves both performance and clarity in this scenario.